Magnetic pulley



Dec. 26, 1950 K. A. BLIND 2,535,719

MAGNETI C PULLEY Filed Dec. 29, 1947 IN V EN TOR.

A TTO/F/VE' Y5.

Patented Dec. 26, 1950 MAGNETIC PULLEY Karl A. Blind, Thiensville, Wis., assignor to Dings Magnetic Separator C o., corporation of Wisconsm Milwaukee, Wis., 2.

Application December 29, 1947, Serial No. 794,407

9 Claims. 1

The present invention relates generally to improvements in magnetic pulleys, and relates more particularly to various improvements in the construction and operation of permanently magnetized pulleys especially adapted to separate magnetic pieces or particles from non-magnetic substances contained in layers or burden of limited depth brought into proximity with the pulleys.

It has long been customary to utilize magnetic pulleys cooperating with conveyor belts or the like for various purposes such as the removal of tramp iron in order to protect the working parts of crushers, grinders pulverizers, and other machinery against breakage; the removal of metal from explosive mixtures so as to prevent sparks and dust explosions or fires; the purification of non-magnetic substances; and the concentration of magnetic materials. As a rule the magnetic tramp iron or particles are intimately embedded within and mixed with a mass of non-magnetic material so that it requires a powerful field of magnetic influence in order to insure effective removal of the magnetic substances while the mixture or burden is bein advanced rapidly through the field. Such sufliciently powerful and dependable magnetic fields could heretofore be established and maintained principally with the aid of electromagnets associated with the magnetic pulleys, and while the operation of the electromagnetic type of pulley is quite satisfactory, it is relatively costly to manufacturer and operate, difficult to install, heavy and cumbersome, and requires considerable attention in order to maintain it in efficient operation. I have discovered that most of these objectionable features may be readily eliminated when treating burden or layers of bulk material of limited depth. by utilizing effective permanent magnets instead of electromagnets in such separating pulleys, and that such improved pulleys also possess numerous other advantages.

:It is therefore a primary object of my present invention to provide an improved permanently magnetic pulley which obviates all of the above mentioned objectionable features of electromagnetic pulleys, but which is also adapted to constantly maintain an efficient magnetic field of relatively high intensity.

Another object of the present invention is to provide a simple, compact and durable magnetic pulley devoid of electric wires and other accessries,and which may be readily installed and subsequently operated without attention and additional maintenance cost or expense.

V ;A fu rther object of my invention is to provide a dependable permanently magnetic pulley as-j semblage composed of relatively few simple parts, and which may be manufactured at moderate cost in various sizes and for diverse uses.

Still another object of this invention is to provide a relatively light but powerful magnetic pulley embodying permanent energizing magnets which possess high magnetic energy and are adapted to retain their magnetism for an in definite period of time,

An additional object of the invention is to provide an improved magnetic pulley which utilizes many interchangeably similar elements adapted to produce pulley units of various lengths by merely adding or removing parts of the assemblage, thus greatly facilitating manufacture of such pulleys and reducing the cost to a minimum.

These and other more specific objects and advantages of the present invention will be apparent from the following detailed description.

A clear conception of the features constituting my invention, and of the mode of manufacturing and of utilizing the improved permanent magnetic pulleys, may be had by referring to the drawing accompanying and forming a part of this: specifl cation in which like reference characters designate the same or similar parts in the various views.

Fig. 1 is a longitudinal section through a typical permanently magnetic crowned pulley embodying the present invention, the section having been taken along the irregular line l--l of Fig. 2;

Fig. 2 is a transverse section through the magnetic pulley of Fig. 1, taken along the line 22; I

and

shown in Figs. 1 and 2.

While the invention has been shown and de-,

scribed herein as having been embodied in a scope or utility of the improvement by virtue of this restricted embodiment since the number andmagnitude of these magnet groups or series may be varied throughout a considerable range without departing from the spirit of my invention.

Referring to the drawing, the typical permanently magnetic pulley shown therein, comprises in general an elongated hollow externally octagonal hub 6 having opposite end supporting bushings or inserts I Secured thereto by welding or Fig. 3 is a perspective View of an assembled magnetic uncrowned pulley of the general type:

otherwise; four annular series each consisting of eight radially disposed permanent magnetic slugs or blocks 8 the inner ends of which snugly engage the outer plane faces 9 of the hub 6; an outer elongated shoe or pole-piece ll) snugly engaging the outer plane surfaces of each longitudinally alined set of the blocks 3 and being clamped thereagainst by means of cap screws ll an annular series of elongated parallel spacer bars l2 interposed between the successive parallel polepieces Ill; an annular end disc or head it coacting with each insert bushing l and with the adjacent ends of the pole-pieces is] and spacer bars [2; and an annular series of-parallel bolts it: for retaining the end heads It upon the supporting inserts and for clamping these heads against the hub ii, pole-pieces It andbarsw,l2. l I

The elongated hub ti is prererably formed of ferrous material such as ordinary steel, and may be of any suitable length adapted to accommodate one or more annular series of the magnetic blocks 8 depending upon the length of pulley face desired; and the supporting inserts l may be formed of similar material and are bored for coaction with a pulley mounting shaft it to which these inserts may be keyed or otherwisefirmly attached. The slugs or blocks 8 a'r'eall of interchangeably similar formation and are preferably constructed of material such as Alnico metal having high magnetic energy and being intensely permanently magnetized; andthese blocks 8 are preferably radially disposed and have plane parallel opposite inner and outer end surfaces, the inner of which snugly engage the outer faces 9 of the hub 6 while the outer block surfaces likewise engage the inner plane faces of the adjacent pole-pieces l8. elongated pole-pieces l which coact with the successive alined rows of magnetized blocks 8 are also formed of ferrous metal such as ordinary steel, and the blocks 3 of each row are clamped firmly between the adjacent pole-piece iii and hub surface 9-by means'of intervening cap screws 11' as depicted in Fig. 1.

The cap screws H are preferably formed ofnon-magnetic material such as brass, and the outer end heads of these screws are confined within sockets ll formed in the pole-pieces it and coact with lock-washers as shown. After the cap screws II have been properly applied, the sockets i'l may be filled with lead or solder so as to provide a smooth pulley periphery; and the pole-pieces llland the blocks 8 must be segregated from each other, this result being ac complished by means of the spacer-bars l2 which are also formed of non-magnetic light material such as aluminum. The spacer bars l2 have tapered or key-stone shaped transverse crosssection and are provided with retainer flanges l8* coacting with the inner surfaces of the adjacent pole-pieces it as illustrated in Fig. 2, arid-both the pole-pieces I0 and the bars 12 may be thickened at their medial portions as in Fig. 1 so 'as to provide a crowned smooth circular pulley face adapted to coact with a material transporting belt'in a well known manner. The interchangeably similar circular end heads it are also preferably formed of light non-magnetic metal to clamp the end heads l4 against the hub 6;;

pole-pieces l0 and spacer bars [2 should also be provided with lock-washers as shown.

As previously indicated, any desired number The of the magnetic slugs 8 of diverse sizes and shapes, may be provided in each of the annular series, and any desired number of these series may also be provided, depending upon the size, shape and capacity or pulley desired; and when a pulley has been manufactured and assembled as hereinabove described, it may be utilized as follows. The mounting shaft It should be journalled in suitable bearings with its axis disposed approximately horizontal, and an endless belt for conveying the burden or mixture of magnetic and non magnetic materials should be caused to coact with the periphery of the horizontal pulley in a-- manner whereby the upper stretch or run of the conveyor belt'is tangent to the uppermost peripheral portion of the pulley while the adjacent bend of the belt snugly engages the pulleyface and advances about the pulley axis.

The intensely magnetized slugs or blocks 3 of the pulley constantly maintain powerful fields of magnetic influence spanning the successive spacer bars t2 and extending a considerablev distance outwardly beyond the periphery of the pulley from each longitudinal edge of each polepiece [G to the ad acent longitudinal edge of the adjacent pole-piece Ill, and these fields are advanced in succession along the conveyor belt bendcoacting with the pulley periphery. When a layer of burden is deposited upon the: upper belt stretch and is advanced into the path of revolution of this advancing series of magnetic fields, the magnetic pieces or particles of the burden are drawn toward the outer surface ofthe travelling belt by magnetic influence and are carried entirely around the belt bend, while the non-magnetic ingredients orparticles of the layer are cascaded by gravity from the midportion of this belt bend and fall free from the The adhering magnetic in-- conveying surface. gredients of the burden layer are carrier downwardly and rearwardly beyond the vertical plane of delivery of the non-magnetic substances, and areultimately removed from the zone of magnetic influence below and beyond the pulley, whereupon these magnetic pieces or particles.

drop "by gravity from the transporting surface? of the belt.

*This separation-of magnetic" and non-magnetic ingredients of the bulk material or burden, is accomplished continuously; automatically and fields, but by utilizing permanent magneticblocks' 8 of proper dimensions formed of materials such as Alnico metal, layers of burden up to two inches in thickness may be effectively treated commercially. The improved magnetic pulleys may therefore be advantageously utilized for the removal of tramp iron in order-to protect machine parts against damage and to prevent dust ignition sparks, and for the purification of mm magnetic substances or concentration vof magnetic substances, thus fitting them fordiverse uses, in various industries.

From the foregoing detailed description it will be apparent that my present invention provides ah' improved magnetic pulley which besides being'simple, compact and durable in construction-,

is also efficient in operation and-flexible in its adaptations. The provision of the hollow hub 6 and light metal spacer bars I2 and end heads l4, reduces the total weight of each pulley to a minimum without sacrificing strength; and the use of interchangeably similar supporting inserts I, blocks 8, pole-pieces l0, spacer bars l2, and end heads l4, reduces the manufacturing cost to a minimum and also greatly facilitates assem: bly of the pulleys. The construction is simplified by eliminating necessity of utilizing electromagnets and the wiring and electrical apparatus required in connection therewith, and by utilizing permanent magnets the pulley will function automatically and most effectively forever and without any attention or maintenance expense. The magnetic blocks 8 also permit manufacture of the improved pulleys in diverse diameters and lengths at but slight additional cost for each selected size, and the completed pulleys may be readily installed and operated by a novice for use on either wet or dry materials.

The opposite end heads l4 provide non-magnetic extensions beyond the path of travels of the conveyor belt, which not only accommodate or compensate for belt wear but also prevent material from entering the space between the belt and the magnetically active face of the pulley; and the non-magnetic spacers I! serve as bridge bars for the magnetic circuits, thus producing effective field distribution around the pulley periphery. Since the strength of the successive symmetrically disposed poles is exactly alike, the flux will be uniformly distributed throughout the magnetic field at each of the successive gaps, and this is not the case with assemblages utilizing horseshoe shaped magnets instead of blocks 8 such as utilized in my improved pulley assemblage. The improved assemblage also insures maximum and uniform magnetic strength throughout the full effective area of the conveyor belt, and the invention has proven highly satisfactory and successful in actual commercial use.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use, herein shown and described, for various modifications within the scope of the appended claims may occur to persons familiar with the art; and it is also contemplated that specific descriptive terms employed herein be given the broadest possible interpretation consistent with the disclosure.

Iclaim:

1. In a magnetic pulley, a hub of magnetic material having polygonal cross-section bounded by plane outer surfaces, an annular series of permanent magnets having inner end faces snugly engaging said hub surfaces, a pole-piece of magnetic material snugly coacting with the outer face of each of said magnets and projecting laterally beyond the adjacent outer faces, and a non-magnetic spacer interposed between each adjacent pair of said pole-pieces and cooperating therewith to form the pulley face, said spacers projecting laterally beyond the laterally projecting portions of said pole-pieces inwardly of said outer magnet faces.

2. In a magnetic pulley, a hub of magnetic material, several spaced annular series of interchangeably similar magnets radiating from said hub, a pole-piece of magnetic material coacting with the outer ends of each axially alined set of magnets of the several series and having edges projecting laterally beyond said outer ends, a non-magnetic spacer interposed between each adjacent pair of said pole-pieces and projecting laterally beneath said edges of the adjacent polepieces, and non-magnetic elongated clamping ill) elements interposed between the adjacent mag nets for directly securing said pole-pieces to said hub and for holding said spacers in place.

3. In a magnetic pulley, a hub of magnetic material having polygonal cross-section bounded by flat surfaces, several spaced annular series of magnets radiating from said hub and "each having an inner face coacting with one of said hub bounding surfaces, an annular series of parallel pole-pieces each coacting with the outer faces of the alined magnets of all of said series and having edges projecting laterally beyond said outer faces, and a non-magnetic spacer interposed between each adjacent pair of said polepieces and projecting laterally beneath said edges of the adjacent pole-pieces.

4. In a magnetic pulley, a hub of magnetic material having polygonal cross-section boundedby flatsurfaces, several spaced'annular series of magnets radiating from said hub and each having an inner face coacting with one of said hub bounding surfaces, an annular series of parallel pole-pieces each coacting with the outer faces of the alined magnets of all of said series and having edges projecting laterally beyond said outer faces, a non-magnetic spacer interposed between .each adjacent pair of said pole-pieces and projecting laterally beneath said edges of the adjacent pole-pieces, and elongated clamping elements connecting each of said pole-pieces with said hub between the successive alined magnets of said series.

5. In a magnetic pulley, a hub of magnetic material, several spaced annular series of magnets radiating from said hub, a pole-piece of magnetic material coacting with the outer ends of each axially alined set of magnets of the several series and having opposite edges: projecting laterally beyond said outer ends, a nonmagnetic spacer interposed between each adjacent pair of said pole-pieces and projecting laterally beneath said edges of the adjacent polepieces, and elongated cLamping elements connecting each of said pole-pieces with said hub between the successive magnets of each set.

6. In a magnetic pulley, a hub of magnetic material, several spaced annular series of magnets radiating from said hub, a pole-piece of magnetic material coacting with the outer ends of each axially alined set of magnets of the several series and having opposite edges projecting laterally beyond said outer ends, a nonmagnetic spacer interposed between each adjacent pair of said pole-pieces and projecting laterally beneath said edges of the adjacent polepieces, elongated clamping elements connecting each of said pole-pieces with said hub between the successive magnets of each set, an end head clamplngly engaging each end of said hub and the adjacent ends of said pole-pieces and spacers, and other elongated clamping elements connecting said end heads between the successive alined sets of said magnets.

7. In a magnetic pulley, a hub of magnetic material, several spaced annular series of interchangeably similar permanent magnets radiating from said hub, a pole-piece of magnetic material coacting with the outer ends of each axially alined set of magnets of the several series and having opposite side edges projecting laterally beyond said outer ends, a non-magnetic spacer interposed between each adjacent pair of said pole-pieces and projecting laterally beneath said edges of the adjacent pole-pieces, an end head of non-magnetic material clampingly engaging I each end of said hub and the adjacent ends of said pole-pieces rand spacers, and elongated clamping elements connecting said end heads and being disposed between the successive alined sets of said magnets.

8. In a magnetic pulley, a hub of magnetic material having several annular series of permanent magnets radiating therefrom, :a pole-apiece of magnetic material coacting with the enter ends of each axially alined set :of radial magnets of 1 theseveral series and each having composite edge portions projecting laterally beyond said outer magnet ends, a non-magnetic spacer interposed between each adjacent 'pair of said pole-pieces and projecting laterallytbeneath said edge portions of the adjacent pole-pieces, and elongated elements for clamping said mole-pieces to said magnets and for simultaneous retaining said spacers'in position.

9.. vIn a magnetic pulley, a hub of magnetic material having several annular series of permanent magnets radiating therefrom, a pole-piece ofmagnetic material coacting with the outer ends of each axially alined set of radial magnets of the several series and each having opposite edge portions projecting laterally beyond :said outer magnet ends, a non-magnetic spacer interposed between each adjacent pair .of said pole-pieces and projecting laterally beneath said edge portions of the adjacent pole-pieces, and elongated elements disposed between the successive magnets of said series for directly clamping said polepieces against the-miter ends of said magnets and for simultaneously clamping said magnets to said hub while :also retaining said spacers in proper position .KARL A. BLIND.

REFERENCES CITED The following references are of record in the file of this patent:

' "UNITED STATES PATENTS 

